A light filter and a spectrometer including the light filter are disclosed. The light filter includes a plurality of filter units having different resonance wavelengths, wherein each of the plurality of filter units includes a cavity layer configured to output light of constructive interference, a Bragg reflection layer provided on a first surface of the cavity layer, and a pattern reflection layer provided on a second surface of the cavity layer opposite to the first surface and configured to cause guided mode resonance of light incident on the pattern reflection layer, the pattern reflection layer including a plurality of reflection structures that are periodically arranged.

Provided is an optical filter including a plurality of bandpass filters having center wavelengths of light that are different from one another, wherein each of the plurality of bandpass filters includes a cavity layer, a first Bragg reflective layer provided on an upper surface of the cavity layer, and a second Bragg reflective layer provided on a lower surface of the cavity layer opposite to the upper surface, wherein the cavity layer has a thickness greater than A/n, where A is a center wavelength of light of each of the bandpass filters and n is an effective refractive index of the cavity layer, and wherein each of the first Bragg reflective layer and the second Bragg reflective layer includes three or more material layers having different refractive indices from one another.

A monitoring system for a power grid includes one or more power transformer monitors. Each power transformer monitor includes a plurality of optical sensors disposed on one or more optical fibers that sense parameters of the power transformer. Each optical sensor is configured to sense a power transformer parameter that is different from a power transformer parameter sensed by at least one other sensor of the plurality of optical sensors. An optical coupler spatially disperses optical signals from the optical sensors according to wavelength. A detector unit converts optical signals of the optical sensors to electrical signals representative of the sensed power transformer parameters.

This disclosure is related to devices, systems, and techniques for precisely measuring a wavelength of an optical signal. For example, a wavemeter system includes processing circuitry, a detector array, a set of optical chips, and a coarse wavelength unit configured to generate a coarse wavelength measurement of the input optical signal. The processing circuitry is configured to select an optical chip from a plurality of optical chips. The detector array is configured to generate a partial interferogram based on the at least the portion of the input optical signal. The processing circuitry is further configured to calculate an optical spectrum of the input optical signal based on the partial interferogram corresponding to the at least the portion of the input optical signal and the calibration matrix and identify, based on the optical spectrum of the input optical signal, the precise wavelength of the input optical signal.

Optical polarization-based devices and techniques are provided to enable low cost construction and easy signal processing to measure the light frequency via measurements of signals associated with a delay between the two orthogonal polarizations after passing through a DGD element and the retardation value of the DGD element without directly measuring the optical frequency. The optical detection may be designed in various configurations. In particular, for example, the optical detection may split the optical output of the DGD into two optical beams with two different optical detectors so that the final frequency information can be deducted into a pair of sine and cosine functions, such as a pair of sine and cosine functions of measured optical signal levels and the retardation value of the DGD element.

Provided are a dual coupler device configured to receive lights of different polarization components, a spectrometer including the dual coupler device, and a non-invasive biometric sensor including the spectrometer. The dual coupler device may include, for example, a first coupler layer configured to receive a light of a first polarization component among incident lights. and a second coupler layer configured to receive a light of a second polarization component among the incident lights, wherein a polarization direction of the light of the first polarization component is perpendicular to a polarization direction of the light of the second polarization component. The first coupler layer and the second coupler layer may be spaced apart from each other and extended along a direction in which the light propagates in the first coupler layer and the second coupler layer.

A chip-based planar Raman spectroscopic measurement system is disclosed comprising at least a semiconductor laser as excitation light source, an output waveguide coupling and delivering laser light out of chip, a photo-detector monitoring the laser optical power, an input waveguide coupling signal light to chip, a planar spectrometer comprising Planar Waveguide Grating (PWG) and an array photo-detectors, and control electronics. In some embodiments the PWG is a fixed frequency Arrayed Waveguide Grating (AWG), the laser is frequency-tunable. In other embodiments, the laser has fixed frequency, the PWG or the AWG is frequency tunable. In either case, the frequency tunability will ensure the recapture of the spectral information missed due to the spectral characteristics of the planar waveguide grating such as the channel spacing of the AWG, resulting in high channel count and high-resolution Raman measurement of sufficient spectral range.

The present invention provides a transmission guided-mode resonant grating integrated spectroscopy device (transmission GMRG integrated spectroscopy device) characterized by comprising, disposed in this order on an optical detector array in which a plurality of diodes are mounted on a substrate made of a semiconductor: a transparent spacer layer; a waveguide layer; a transparent buffer layer provided as desired; a transmission metallic grating layer having a thickness causing surface plasmon; and a transparent protection film layer which is provided as desired.

An optical device and a spectral detection apparatus are provided. The optical device includes an optical waveguide, including: a polychromatic light channel configured to transport a polychromatic light beam, and provided with a light incident surface for receiving the incident polychromatic light beam at an input end of the polychromatic light channel; a chromatic dispersion device arranged downstream from the polychromatic light channel in an optical path and configured to separate the polychromatic light beam from the polychromatic light channel into a plurality of monochromatic light beams; and a plurality of monochromatic light channels arranged downstream from the chromatic dispersion device in the optical path and configured to respectively conduct the plurality of monochromatic light beams with different colors from the chromatic dispersion device. Monochromatic light output surfaces are respectively provided at output ends of the plurality of monochromatic light channels and configured to output the monochromatic light beams.

A LADAR that includes a transmitter and a receiver. The transmitter includes a laser for delivering an original beam pulse. A nonlinear optic receives the original beam pulse and outputs wavelengths as an incident beam pulse. Output optics direct the incident beam pulse onto a target, which reflect from the target as a reflected beam pulse. The receiver includes a dispersive optic for temporally dispersing the wavelengths in the reflected beam pulse, thereby producing a dispersed beam pulse. A single-pixel sensor receives the dispersed beam pulse, and measures and outputs a separate intensity value for each of the wavelengths in the dispersed beam pulse based at least in part on the temporal dispersion of the wavelengths. A processor receives the intensity values from the dispersed beam pulse, correlates the intensity values with the wavelengths, compares the intensity values to known intensity values from the incident beam pulse, produces ratio values for each of the wavelengths, and produces reflectance data in regard to the target from the ratio values.